2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/75587We extend Krupnik's criterion of self-adjointness of the Cauchy singular integral operator to the case of finitely connected domains. The main aim of the paper is to present a new approach for proof of the criterion.5 pages ; added references; result extended to the case of finitely connected domainsFunctional AnalysisComplex VariablesPrimary 47G10, 46E20; Secondary 47B38, 45P05, 47A45text